Area judging apparatus

1. An area judging apparatus for judging multiple areas including character portions, photograph portions and dot portions, comprising: binarizing means which designates a block of a predetermined number of pixels centering around target pixels among the image data as a mask, and compares the pixels in said mask with a threshold to binarize it into binary values; linkage degree-calculating means for calculating the linkage degree indicating the linking conditions of black pixels, based on the number of black pixels for each line in each direction in said binarizing mask; density parameter-calculating means for calculating the density parameter from the density of the black pixels in said binarizing mask; and area judging means for designating said linkage degree and said density parameter as the characteristic value, and judging an area of said target pixels based on the characteristic value; wherein said linkage degree-calculating means counts the number of black pixels in each line in the main scanning direction as a first value and in the sub scanning direction as a second value from the results of binarization in said mask, and designates the larger of said first and second values as the linkage degree.

2. An area judging apparatus according to claim 1, wherein said linkage degree-calculation means counts the number of successive black pixels in each line.

3. An area judging apparatus for judging multiple areas including character portions, photograph portions and dot portions, comprising: binarizing means which designates a block of a predetermined number of pixels centering around target pixels among the image data as a mask, and compares the pixels in said mask with a threshold to binarize it into binary values; linkage degree-calculating means for calculating the linkage degree indicating the linking conditions of black pixels, based on the number of black pixels for each line in each direction in said binarizing mask; density parameter-calculating means for calculating the density parameter from the density of the black pixels in said binarizing mask; and area judging means for designating said linkage degree and said density parameter as the characteristic value, and judging an area of said target pixels based on the characteristic value; wherein said linkage-calculating means counts the number of successive black pixels in each line in both the main scanning direction and in the sub scanning direction as first and second values respectively from the results of the binarization in said mask, adds the first values for successive plural lines in the main scanning direction so as to create a first sum, adds the second values for successive plural lines in the sub scanning direction so as to create a second sum, and designates the larger of the first sum or the second sum as the linkage degree.

4. An area judging apparatus for judging multiple areas including character portions, photograph portions and dot portions, comprising: binarizing means which designates a block of a predetermined number of pixels centering around target pixels among the image data as a mask, and compares the pixels in said mask with a threshold to binarize it into binary values; linkage degree-calculating means for calculating the linkage degree indicating the linkage condition of black pixels, based on the number of black pixels for each line in each direction in said binarizing mask; and area judging means for designating said linkage degree as a characteristic value, and judging an area of said target pixels based on the characteristic value; wherein said linkage degree-calculating means counts the number of successive black pixels in each line in the main scanning direction as a first value, in the sub scanning direction as a second value, and in two diagonal directions at 45.degree. as third and fourth values respectively from the results of binarization in said mask, adds the values for said successive plural lines in each of said directions respectively so as to create first, second, third and fourth sums, and designates the largest of said sums as the linkage degree.

5. An area judging apparatus according to claim 4, wherein normalization is performed according to the difference in the total pixel number counted in each direction.

6. An area judging apparatus for judging multiple areas including character portions, photograph portions and dot portions, comprising: binarizing means which designates a block of a predetermined number of pixels centering around target pixels among the image data as a mask, and compares the pixels in said mask with a threshold to binarize it into binary values; linkage degree-calculating means for calculating the linkage degree indicating the linking conditions of black pixels, based on the number of black pixels for each line in each direction in said binarizing mask; density parameter-calculating means for calculating the density parameter from the density of the black pixels in said binarizing mask; and area judging means for designating said linkage degree and said density parameter as the characteristic value, and judging an area of said target pixels based on the characteristic value; wherein said linkage degree-calculating means counts the number of successive black pixels in each line in the main scanning direction as a first value, in the sub scanning direction as a second value, and in two diagonal directions at 45.degree. as third and fourth values respectively from the results of binarization in said mask, adds the values for said successive plural lines in each of said directions respectively so as to create first, second, third and fourth sums, and designates the largest of said sums as the linkage degree.

7. An area judging apparatus according to claim 6, wherein normalization is performed according to the difference in the total pixel number counted in each direction.

8. An area judging apparatus for judging multiple areas including character portions, photograph portions and dot portions, comprising: binarizing means which designates a block of a predetermined number of pixels centering around target pixels among the image data as a mask, and compares the pixels in said mask with a threshold to binarize it into binary values; linkage degree-calculating means for calculating the linkage degree indicating the linking conditions of black pixels, based on the number of black pixels for each line in each direction in said binarizing mask; density parameter-calculating means for calculating the density parameter from the density of the black pixels in said binarizing mask; and area judging means for designating said linkage degree and said density parameter as the characteristic value, and judging an area of said target pixels based on the characteristic value; wherein said linkage degree-calculating means counts the number of successive black pixels in each line both in the main scanning direction and the sub scanning direction as first values and second values respectively from the results of binarization in said mask, sequentially adds the first values for successive plural lines in the main scanning direction so as to create at least two first sums, sequentially adds the second values of successive plural lines in the sub scanning direction so as to create at least two second sums, and further determines the difference values (maximum value-minimum value) of the first sums in the main scanning direction and second sums in the sub scanning direction, respectively, and finally designates the largest of said difference values as the linkage degree.